At present, touch technologies are widely used in intelligent devices to achieve human-computer interaction. Touch screens may comprise on-cell touch screens and in-cell touch screens. In the on-cell touch screen, for example, a touch panel is disposed between a color filter substrate and a corresponding polarizing plate of a liquid crystal panel, and thereby a touch sensor is disposed on the liquid crystal panel. The on-cell touch screen is thick and heavy and thus it is difficult to meet the growing demands for thin and light display products. In the in-cell touch screen, the touch sensor is disposed inside the liquid crystal panel and a cover glass is attached to the liquid crystal panel, and the in-cell touch screen has the advantages of high transmittance, high lamination rate, light weight, small thickness and so on. The in-cell touch screen generally comprises a color filter substrate and an array substrate. The color filter substrate generally comprises a glass substrate, a black matrix, a color filter layer, an overcoat layer and a touch electrode.